Abstract P227: Paradoxical Associations of Occupational and Non-Occupational Sedentary Behavior With Cardiovascular Risk Factors in Desk Workers

Introduction: Sedentary behavior (SB) has emerged as a cardiovascular disease (CVD) risk factor, independent of physical inactivity. Yet, preliminary research suggests that these relationships may differ if SB is accumulated during occupational or non-occupational time. Thus, we examined associations of SB with CVD risk factors, by domain, in desk workers. Hypothesis: We hypothesized that non-occupational SB would have more unfavorable associations with CVD risk factors compared to occupational SB. Methods: This cross-sectional, secondary analysis of baseline data from the RESET BP clinical trial included 269 desk workers (age=45.2±11.6 years; 83.5% white; 59.3% female). Total SB was measured by activPAL3 and was partitioned into occupational and non-occupational domains. CVD risk factors included resting and nocturnal systolic/diastolic blood pressure (SBP/DBP) and heart rate (HR), resting carotid-femoral (cf) and carotid-radial (cr) pulse wave velocity (PWV), and heart rate variability (HRV) [i.e., natural log transformed standard deviation of R-R intervals (lnSDNN), root mean square of successive differences (lnRMSSD), and high frequency (lnHF)]. Adjusted linear regression estimated associations of SB with CVD risk factors. A Wald test compared the beta-coefficients associating occupational vs. non-occupation SB with these CVD risk factors. Results: Participants spent 69%, 77%, and 64% of their time in total, occupational, and non-occupational SB, respectively. Agnostic of the domains, a 1-hour increase in total SB was only associated with higher cfPWV (0.18 m/s; p<0.05). A 1-hour increase in occupational SB was associated with lower (favorable) resting DBP and nocturnal SBP and DBP (-1.02, -1.52, and -1.12 mmHg, respectively; p<0.05). Paradoxically, a 1-hour increase in non-occupational SB was associated with higher (unfavorable) resting DBP (1.04 mmHg), HR (1.07 beat/minute), cfPWV (0.23 m/s), nocturnal SBP (1.41 mmHg), and lower resting lnSDNN (-0.07), lnRMSSD (-0.10), and lnHF (-0.18). Wald tests revealed significant differences in beta coefficients (p<0.05 for all) for all these outcomes where occupational SB was favorably associated with these CVD risk factors while non-occupational SB was unfavorably associated with these CVD risk factors. Conclusions: While desk workers accumulate high amounts of occupational and non-occupational SB, paradoxical associations with CVD risk were observed with non-occupational SB being unfavorable and occupational SB being favorable for CVD risk factors. Confirmation is needed in longitudinal and experimental studies.